Indicator for party-line telephones.



E. BOWMAN.

INDICATOR FOR PARTY LINE TELEPHONES.

APPLICATION FILED JULY 23, 1912 Patented J an. 26, 1915.

Witnesses W. x? M, 51 7% THE NORRIS PETERS CO PHOTO-LITHCL, WASHING FUN D c i l STATES PATNT OFT TOE.

ELHANAN BOWMAN, OF ELMWOOD, ONTARIO, CANADA, ASSIGNOR 0F ONE-HALF TO CHRISTIAN ROTH MILLER, OF BERLIN, CANADA.

INDICATOR FOR PARTY-LINE TELEPHONES.

Specification of Letters Patent.

Patented Jan. 26, 1915.

To all whom it may concern Be it known that I, ELHANAN BOWMAN, a subject of the King of Great Britain, resident of the town of Elmwood, county of Bruce, Province of Ontario, in the Dominion of Canada, have invented certain new and useful Improvements in Indicators for Party-Line Telephones, described in the following specification and illustrated in the accompanying drawings, that form part of the same.

The essential feature of the present invention consists in the novel construction and arrangement of parts whereby a sounding device is operated by the receiver hook and whereby a temporary bridging of the receiver circuit is effected.

The objects of the invention are to obviate the annoyance of having meddlesome persons listening on party telephone lines and to provide a simple device which will give a clear indication of the presence of a third party to the parties properly using the line.

The further object of this invention is to prevent a third party sneaking in on the line by holding the receiver hook part way open.

In the drawings, Figure 1 is a perspective view of a portion of a telephone showing a portion of the receiver hook and a supporting bracket and my invention applied thereto. Fig. 2 is a plan View of the device.

Like numerals of reference indicate corresponding parts in each figure.

Referring to the drawings, 1 is a bracket member preferably formed with an open triangular shaped portion 2 adapted to be secured to the inner wall of the telephone box with the perpendicular portion 3 arranged adjacent to the receiver hook slot 4: in the box.

5 is a rigid arm extending substantially at right angles from the outer vertical side of the portion 2 and having an offset portion 6.

7 is the receiver hook pivotally supported at its inner end upon the screw 8 secured in the offset end of the arm 5. The arm of the receiver hook extends through the triangular orifice in the bracket 1 and one side face thereof is adapted to engage the perpendicular side of said orifice.

9 is the receiver carried on the hook 7.

10 is a bracket rigid with the arm 5 and extending beneath the receiver hook and supporting the contact plates 11 which are member may be used if desired. The free end 15 extends close to the path of movement of the receiver hook.

16 is a small metal plate insulated from and preferably adjustably secured to the side face of the arm of the receiver hook,

said plate having a laterally projecting sloping portion 17 adapted on the movement of the receiver hook to engage the free end 15 of the sounding member 13. The sounding member 13 is electrically connected by the wire 18 to a suitable binding post 19 arranged in the receiver circuit and the plate 16 carried on the receiver hook is electrically connected by a wire 26 to a binding post 21 in the other branch of the receiver circuit.

In the operation of this device when the receiver is removed from the hook the said hook moves up to the top of the slot being spring operated. As the receiver hook moves upwardly the laterally extending sloping portion of the plate 16 engages the end of the sounder 13 and springs the said sounder and as the plate moves farther the said sounder slips over the bottom edge of the plate and vibrates giving forth a resonant sound which is carried over the transmitter so that any other person connected on the line may hear the sound. A similar sound is made on the placing of the receiver on the hook, the sloping plate 17 engaging and springing the sounder in the opposite direction.

The sounder and its operating plate carried by the receiver hook are electrically connected to the receiver circuit through the wires 18 and 20 and the said sounder and plate are so arranged that they engage prior to the closing of the ordinary circuits through the contacts 11. The engagement of the plate 16 and sounder 13 causes a bridge or short circuit on the receiver circuit, consequently if a person attempts to sneak in on the line by holding the receiver hook so that it does not release the sounder, their attempt will be frustrated as their receiver will be short circuited and they will be unable to hear anything from the; line.

From this description it will be understood that when two parties are talking and a third party attempts to cut in the sounder will indicate to both parties on the line that another person has removed their receiver and as most party lines have only a limited number of telephones the sounders can be tuned with suliicient variation for the various parties to be able to locate who theoifender is and when such condition exists the mal-practice of listening in will, of course, be very rapidly discontinued.

The device is very simple and costs very little to install and does not interfere in any way with the operation of any of the parts of the telephone, further, it may be applied to difierent makes of telephones very readily.

Another important feature in the present invention is that the sounder produces a very resonant tone which can be heard for some distance in the house where the instrument is located and this acts as a further deterrent to the practice. of listening and enables parents to hear if children in the house tamper with the instrument.

What I claim as my invention is 1. In an indicator for party line telephones, the combination with the receiver hook, of a vibratory spring sounder rigidly secured and extending into the path of movement of the receiver hook and adapted to be engaged directly thereby to'cause it to resound.

2. In an indicator for party line telephones, the combination with the receiver hook, of a vibrator arranged adjacent to the receiver hook, and a sloping plate member secured to said receiver hook and adapted to engage and spring said vibrator.

3. In an indicator for party line telephones, the combination with a receiver hook, of a spring metal vibrator having its free end arranged adjacent to said hook, a plate adjustably secured to said hook and having a laterally extending sloping projection adapted to engage the free end of said vibrator.

4. In an indicator for party line telephones, the combination with a receiver hook and receiver, of a sounder arranged adjacent to said hook and suitably insulated, a wire electrically connecting said sounder to one branch of the receiver circuit, a member projecting from said receiver hook and insulated therefrom and adapted to engage and operate said sounder and to form an electrical connection therewith, and a wire connected to said projection and to the other branch of the receiver circuit.

Signed at the village of Elmwood this 26th day of June 1912.

ELHANAN BOWMAN.

Witnesses MICHAEL HAUG, HENRY GLAUSER.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

